[Drbd-dev] Re: drbd in linux-ha cvs

Philipp Reisner philipp.reisner at linbit.com
Tue Sep 7 14:56:19 CEST 2004


On Tuesday 07 September 2004 14:03, Lars Marowsky-Bree wrote:
> On 2004-09-07T12:49:26,
>
>    Lars Ellenberg <lars.ellenberg at linbit.com> said:
> > it is more clean to have one ioctl, get the full info, and output that.
> > I feel uneasy about introducing additional races by using several ioctls
> > in a row (even if they all finish within one second). of course, once we
> > have that info it could be stale already, but at least we have the
> > guarantee that at some point in time it was correct.
>
> Well, even if not correct, so at least it was consistent ;-)
>
> It's also much easier to maintain in the external script, and less
> likely to be gotten wrong in the script.
>
> > as soon as we have a sane interface, I don't expect the internals to
> > change so often, so the "maintenance trouble" is very low, either way.
>
> Well, even if eventually change and export more data, that's more
> maintainable.
>
> I don't need writes to the generation counters, but getting at all that
> information to know where to move things would be quite helpful.
>

My initial understanding was that this read-generation counters
operation would read it off the disk (== run while the DRBD 
module is not loaded). Do you mean that ? Or do you want to have
an ioctl to ask the module for the current value of the countes ?

-philipp
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